In known percussion devices an impact is produced using a reciprocating percussion piston, whose motion is typically generated hydraulically or pneumatically and in some cases electrically or by means of a combustion engine. A stress pulse is produced in the tool, such as a drill rod, when the percussion piston strikes the impact surface of a shank adapter or tool.
The known percussion devices have a drawback that the reciprocating motion of the percussion piston generates dynamic acceleration forces that make the control of the apparatus difficult. As the percussion piston accelerates in the striking direction, at the same time the body of the percussion device tends to move in the opposite direction so as to alleviate the pressing force of a drill bit or a tool tip with respect to the material to be treated. In order to maintain the pressing force of the drill bit or the tool sufficient against the material to be treated, it is necessary to push the percussion device with sufficient force towards the material. This, in turn, brings about a problem that the extra force must be taken into account both in the supporting structures of the percussion device and elsewhere, as a result of which the size and mass of the apparatus as well as the manufacturing costs will increase. Inertia resulting from the mass of the percussion piston restricts the frequency of the reciprocating motion of the percussion piston, and thus, the impact frequency, which, instead, should be considerably raised from the present level in order to achieve a more efficient result. The result of the current solutions is considerable deterioration of operating efficiency, however, and therefore it is not possible in practice.